Geology and geochronology of the Tana Basin, Ethiopia: LIP volcanism, super eruptions and Eocene–Oligocene environmental change

A. R. Prave; C. R. Bates; C. H. Donaldson; Harry Toland; D. J. Condon; D. Mark; T. D. Raub

doi:10.1016/j.epsl.2016.03.009

Geology and geochronology of the Tana Basin, Ethiopia: LIP volcanism, super eruptions and Eocene–Oligocene environmental change

A. R. Prave, C. R. Bates, C. H. Donaldson, Harry Toland, D. J. Condon, D. Mark, T. D. Raub

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New geological and geochronological data define four episodes of volcanism for the Lake Tana region in the northern Ethiopian portion of the Afro–Arabian Large Igneous Province (LIP): pre-31 Ma flood basalt that yielded a single 40Ar/39Ar age of 34.05±0.54/0.56 Ma; thick and extensive felsic ignimbrites and rhyolites (minimum volume of 2–3×103 km3) erupted between 31.108±0.020/0.041 Ma and 30.844±0.027/0.046 Ma (U–Pb CA-ID-TIMS zircon ages); mafic volcanism bracketed by 40Ar/39Ar ages of 28.90±0.12/0.14 Ma and 23.75±0.02/0.04 Ma; and localised scoraceous basalt with an 40Ar/39Ar age of 0.033±0.005/0.005 Ma. The felsic volcanism was the product of super eruptions that created a 60–80 km diameter caldera marked by km-scale caldera-collapse fault blocks and a steep-sided basin filled with a minimum of 180 m of sediment and the present-day Lake Tana. These new data enable mapping, with a finer resolution than previously possible, Afro–Arabian LIP volcanism onto the timeline of the Eocene–Oligocene transition and show that neither the mafic nor silicic volcanism coincides directly with perturbations in the geochemical records that span that transition. Our results reinforce the view that it is not the development of a LIP alone but its rate of effusion that contributes to inducing global-scale environmental change

Iaith wreiddiol	Saesneg
Tudalennau (o-i)	1-8
Nifer y tudalennau	8
Cyfnodolyn	Earth and Planetary Science Letters
Cyfrol	443
Dyddiad ar-lein cynnar	19 Maw 2016
Dynodwyr Gwrthrych Digidol (DOIs)	https://doi.org/10.1016/j.epsl.2016.03.009
Statws	Cyhoeddwyd - 01 Meh 2016

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10.1016/j.epsl.2016.03.009Trwydded: Aneglur 1

Geology and geochronology of the Tana Basin, Ethiopia: LIP volcanism, super eruptions and Eocene-Oligocene environmental changeLlawysgrif awdur wedi’i dderbyn, 9.19 MBTrwydded: CC BY-NC-ND
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@article{864f758be6e24fedaeaeddc26e3dad76,

title = "Geology and geochronology of the Tana Basin, Ethiopia: LIP volcanism, super eruptions and Eocene–Oligocene environmental change",

abstract = "New geological and geochronological data define four episodes of volcanism for the Lake Tana region in the northern Ethiopian portion of the Afro–Arabian Large Igneous Province (LIP): pre-31 Ma flood basalt that yielded a single 40Ar/39Ar age of 34.05±0.54/0.56 Ma; thick and extensive felsic ignimbrites and rhyolites (minimum volume of 2–3×103 km3) erupted between 31.108±0.020/0.041 Ma and 30.844±0.027/0.046 Ma (U–Pb CA-ID-TIMS zircon ages); mafic volcanism bracketed by 40Ar/39Ar ages of 28.90±0.12/0.14 Ma and 23.75±0.02/0.04 Ma; and localised scoraceous basalt with an 40Ar/39Ar age of 0.033±0.005/0.005 Ma. The felsic volcanism was the product of super eruptions that created a 60–80 km diameter caldera marked by km-scale caldera-collapse fault blocks and a steep-sided basin filled with a minimum of 180 m of sediment and the present-day Lake Tana. These new data enable mapping, with a finer resolution than previously possible, Afro–Arabian LIP volcanism onto the timeline of the Eocene–Oligocene transition and show that neither the mafic nor silicic volcanism coincides directly with perturbations in the geochemical records that span that transition. Our results reinforce the view that it is not the development of a LIP alone but its rate of effusion that contributes to inducing global-scale environmental change",

keywords = "Eocene-Oligocene transition, Flood basalt, LIP, Lake Tana, Super eruption",

author = "Prave, {A. R.} and Bates, {C. R.} and Donaldson, {C. H.} and Harry Toland and Condon, {D. J.} and D. Mark and Raub, {T. D.}",

note = "Funding Information: We thank the University of Addis Ababa and H. Dibabe and the late Prof. M. Umer for logistical support, and Prof. H. Lamb and D. Clewley, University of Aberystwyth, and D. Herd, A. Calder and A. Mackie, University of St. Andrews, for assistance. Dr. N. Atkinson at the NERC Isotope Geosciences Laboratory performed the U–Pb dating analyses. This work was supported by NERC Grants NE/D012996/1 and NER/B/S/2002/00540 and NIGFSC IP/1024/0508 . Three anonymous reviewers helped improve this manuscript. Publisher Copyright: {\textcopyright} 2016 Elsevier B.V.",

year = "2016",

month = jun,

day = "1",

doi = "10.1016/j.epsl.2016.03.009",

language = "English",

volume = "443",

pages = "1--8",

journal = "Earth and Planetary Science Letters",

issn = "0012-821X",

publisher = "Elsevier",

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TY - JOUR

T1 - Geology and geochronology of the Tana Basin, Ethiopia: LIP volcanism, super eruptions and Eocene–Oligocene environmental change

AU - Prave, A. R.

AU - Bates, C. R.

AU - Donaldson, C. H.

AU - Toland, Harry

AU - Condon, D. J.

AU - Mark, D.

AU - Raub, T. D.

N1 - Funding Information: We thank the University of Addis Ababa and H. Dibabe and the late Prof. M. Umer for logistical support, and Prof. H. Lamb and D. Clewley, University of Aberystwyth, and D. Herd, A. Calder and A. Mackie, University of St. Andrews, for assistance. Dr. N. Atkinson at the NERC Isotope Geosciences Laboratory performed the U–Pb dating analyses. This work was supported by NERC Grants NE/D012996/1 and NER/B/S/2002/00540 and NIGFSC IP/1024/0508 . Three anonymous reviewers helped improve this manuscript. Publisher Copyright: © 2016 Elsevier B.V.

PY - 2016/6/1

Y1 - 2016/6/1

N2 - New geological and geochronological data define four episodes of volcanism for the Lake Tana region in the northern Ethiopian portion of the Afro–Arabian Large Igneous Province (LIP): pre-31 Ma flood basalt that yielded a single 40Ar/39Ar age of 34.05±0.54/0.56 Ma; thick and extensive felsic ignimbrites and rhyolites (minimum volume of 2–3×103 km3) erupted between 31.108±0.020/0.041 Ma and 30.844±0.027/0.046 Ma (U–Pb CA-ID-TIMS zircon ages); mafic volcanism bracketed by 40Ar/39Ar ages of 28.90±0.12/0.14 Ma and 23.75±0.02/0.04 Ma; and localised scoraceous basalt with an 40Ar/39Ar age of 0.033±0.005/0.005 Ma. The felsic volcanism was the product of super eruptions that created a 60–80 km diameter caldera marked by km-scale caldera-collapse fault blocks and a steep-sided basin filled with a minimum of 180 m of sediment and the present-day Lake Tana. These new data enable mapping, with a finer resolution than previously possible, Afro–Arabian LIP volcanism onto the timeline of the Eocene–Oligocene transition and show that neither the mafic nor silicic volcanism coincides directly with perturbations in the geochemical records that span that transition. Our results reinforce the view that it is not the development of a LIP alone but its rate of effusion that contributes to inducing global-scale environmental change

AB - New geological and geochronological data define four episodes of volcanism for the Lake Tana region in the northern Ethiopian portion of the Afro–Arabian Large Igneous Province (LIP): pre-31 Ma flood basalt that yielded a single 40Ar/39Ar age of 34.05±0.54/0.56 Ma; thick and extensive felsic ignimbrites and rhyolites (minimum volume of 2–3×103 km3) erupted between 31.108±0.020/0.041 Ma and 30.844±0.027/0.046 Ma (U–Pb CA-ID-TIMS zircon ages); mafic volcanism bracketed by 40Ar/39Ar ages of 28.90±0.12/0.14 Ma and 23.75±0.02/0.04 Ma; and localised scoraceous basalt with an 40Ar/39Ar age of 0.033±0.005/0.005 Ma. The felsic volcanism was the product of super eruptions that created a 60–80 km diameter caldera marked by km-scale caldera-collapse fault blocks and a steep-sided basin filled with a minimum of 180 m of sediment and the present-day Lake Tana. These new data enable mapping, with a finer resolution than previously possible, Afro–Arabian LIP volcanism onto the timeline of the Eocene–Oligocene transition and show that neither the mafic nor silicic volcanism coincides directly with perturbations in the geochemical records that span that transition. Our results reinforce the view that it is not the development of a LIP alone but its rate of effusion that contributes to inducing global-scale environmental change

KW - Eocene-Oligocene transition

KW - Flood basalt

KW - LIP

KW - Lake Tana

KW - Super eruption

UR - http://hdl.handle.net/2160/43338

UR - http://www.scopus.com/inward/record.url?scp=84960953842&partnerID=8YFLogxK

U2 - 10.1016/j.epsl.2016.03.009

DO - 10.1016/j.epsl.2016.03.009

M3 - Article

SN - 0012-821X

VL - 443

SP - 1

EP - 8

JO - Earth and Planetary Science Letters

JF - Earth and Planetary Science Letters

ER -

Geology and geochronology of the Tana Basin, Ethiopia: LIP volcanism, super eruptions and Eocene–Oligocene environmental change

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